PostgreSQL 9.4.1 Documentation
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# DISCARD

## Name

DISCARD -- discard session state

## Synopsis

    DISCARD { ALL | PLANS | SEQUENCES | TEMPORARY | TEMP }

## Description

`DISCARD` releases internal resources associated with a database session. This command is useful for partially or fully resetting the session's state. There are several subcommands to release different types of resources; the `DISCARD ALL` variant subsumes all the others, and also resets additional state.

## Parameters

`PLANS`

  Releases all cached query plans, forcing re-planning to occur the next time the associated prepared statement is used.

`SEQUENCES`

  Discards all cached sequence-related state, including `currval()`/`lastval()` information and any preallocated sequence values that have not yet been returned by `nextval()`. (See CREATE SEQUENCE for a description of preallocated sequence values.)

`TEMPORARY` or `TEMP`

  Drops all temporary tables created in the current session.

`ALL`

  Releases all temporary resources associated with the current session and resets the session to its initial state. Currently, this has the same effect as executing the following sequence of statements:

      SET SESSION AUTHORIZATION DEFAULT;
      RESET ALL;
      DEALLOCATE ALL;
      CLOSE ALL;
      UNLISTEN *;
      SELECT pg_advisory_unlock_all();
      DISCARD PLANS;
      DISCARD SEQUENCES;
      DISCARD TEMP;

## Notes

`DISCARD ALL` cannot be executed inside a transaction block.

## Compatibility

`DISCARD` is a PostgreSQL extension.

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